1. Field of the Invention
This invention relates to portable cautery devices, and more particularly to cautery devices powered by laser arrangements.
2. Prior Art
Hemostasis, the stopping or prevention of blood loss, is a matter of urgent concern in many areas of clinical medicine including surgery, trauma and obstetrics. If not stopped in a timely manner, severe bleeding leads to certain death. Bleeding can be caused by accidental conditions during a trauma, or during surgery where tissue and vessels have to be cut to have access to the target site or to remove an organ or local tissue. Small bleeding can usually be stopped using simple means, but more intense bleeding is more difficult to stop. Intense bleeding is the prevalent cause of death following severe trauma such as bullet or stab wounds.
An electro-cautery device is usually used by doctors and surgeons during surgery to stop or prevent the bleeding, or they can also simply tie the blood vessel when the bleeding is too intense and the source can be localized. The electro-cautery device is based on the use of radio-frequency electrical current to cauterize the bleeding site. This implies the use of high voltage electrical energy, which can be sometimes more harmful than the bleeding itself when used in certain areas of the human body such as the brain or the heart. In such areas of the human body, the electro-cautery device can not be used to stop undesirable bleeding. The electro-cautery device is efficient only on small vessels of less than approximately 1.5 mm. diameter, and is inefficient on intense bleeding typically found in severe trauma situations such as bullet or stab wounds. The electro-cautery equipment also requires the availability of a utility current source such as 110 or 220 VAC, and therefore is not portable and cannot be used outdoors.
Direct laser energy can also be utilized to cauterize bleeding tissues. However, current operating room practice in laser cautery and laser ablation requires burdensome procedures made necessary by the fact that laser devices are constructed in such a manner that the laser light is visible to the surgeons and nurses conducting the procedure. To protect against injury from laser, medical personnel must wear protective eyewear to protect their eyes from light injury. Such protective eyewear are particularly burdensome as they are unusually heavily tinted and therefore, thus also interfering with good viewing of the patient and body tissue of the patient during an operation. The tint of protective eyewear, necessary to block laser light, creates a low contrast field of view which makes it difficult to distinguish between different types of body tissue.
In the present invention, we teach of a novel method and construction of a preferred embodiment to stop or prevent the bleeding under any condition, including in proximity of the heart or the brain, or in absence of a utility electrical supply such as in outdoors environment. The medical procedure to stop bleeding using this invention is very similar to standard procedures commonly practiced by doctors and surgeons. A dedicated medical forceps is used to clamp the bleeding site or local blood vessel(s) and thus temporarily stops or prevents the bleeding. The tip of the forceps is then locally and quickly heated up by a localized heat source such as small electric heater or a fiber-coupled infrared laser beam to such a temperature that the tissue and vessels within the clamped area are cauterized and welded together. This process efficiently closes all the local vessels, thereby stopping and/or preventing the bleeding.
Animal studies on live, anesthetized rabbits have demonstrated the efficacy of the device and procedure. Various vessels in the mesentery tissue of the small intestine of the rabbits are quickly and effectively cauterized using this invention. The studies have also shown that this invention can effectively cauterize large vessels such as the Aorta of a rabbit, which could not be cauterized with the electro-cautery system.
In this invention, no electrical current is flowing through the tip of the instrument thereby eliminating any risk of electrical shock when used around the heart or the brain of a patient. The energy delivered to the tip of the instrument is entirely contained within the tip and results in essentially no collateral damage to surrounding tissues. The energy necessary to heat up the tip of the instrument can be generated by a small and efficient infrared semiconductor laser. The infrared laser beam is then delivered to the tip of the instrument through a small optical fiber and absorbed by the tip. The device can be battery operated, self-contained and can easily be hand-held, and therefore can be used in any environment or in places where no utility electrical source is available such as outdoors.
The present invention provides for a completely shielded laser transmission path. The laser fiber optic conductor is housed within an opaque heating tip, thus preventing the leakage of laser light from the instrument into the operating room. Other procedures for the present invention, include the welding together of body tissue. A dedicated medical forceps may be utilized to clamp and hold together the body tissues to be welded together. The tip of the forceps may then be locally and quickly heated up to a localized heat source such as a small electric heater or a fiber-coupled infrared laser beam to such a temperature that the tissues within the clamped area are welded together. A further embodiment of the present invention includes the use of such a device to cut and dissect tissues. For example, by activating the device for longer duration at the desired temperature, the tip of these instruments may be utilized to vaporize the tissue contained between the clamped section, while the tissue immediately adjacent the clamped section is heated to such a temperature so as to coagulate that tissue, thus providing simultaneous cutting and coagulation action.
The animals involved in the development of this invention were procured, maintained, and used in accordance with the Federal Animal Welfare Act and the Guide for Care and Use of Laboratory Animal, prepared by the Institute of Laboratory Animal Resources--National Research Council. The animal experiments were performed at NEMC, which is fully accredited by the AAALAC. The protocol was approved by NEMC Animal Research Committee and USAF Human/Animal Use Committee.